On 6/16/22 23:07, Yu Zhao wrote: > On Thu, Jun 16, 2022 at 11:02 AM Vlastimil Babka <vbabka@xxxxxxx> wrote: >> >> >> > @@ -3794,19 +3805,29 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone, >> > struct list_head *list; >> > struct page *page; >> > unsigned long flags; >> > + unsigned long __maybe_unused UP_flags; >> > >> > - local_lock_irqsave(&pagesets.lock, flags); >> > + /* >> > + * spin_trylock_irqsave is not necessary right now as it'll only be >> > + * true when contending with a remote drain. It's in place as a >> > + * preparation step before converting pcp locking to spin_trylock >> > + * to protect against IRQ reentry. >> > + */ >> > + pcp_trylock_prepare(UP_flags); >> > + pcp = pcp_spin_trylock_irqsave(zone->per_cpu_pageset, flags); >> > + if (!pcp) >> >> Besides the missing unpin Andrew fixed, I think also this is missing >> pcp_trylock_finish(UP_flags); ? > > spin_trylock only fails when trylock_finish is a NOP. True, so it's not an active bug, but I would still add it, so it's not confusing and depending on non-obvious details that might later change and break the code.
